Annealing leer



J. L. DRAKE ANNEALING LEER May 16, 1933.

Filed May l1. 1951 INVENTOR Jhn L Dra/(e ATTORNEY JOHN L. BRAKE,

Patented May 16, 1933 UNITED STATES vP.AfrENT.oFFlcE ANNEALI'NG LEER Application filed .May-11,

The present invention relates to improvements in annealing leers or ovens and more especially to those designed for the annealing of sheet glass.

In annealing sheet glass according to one well known method, the sheet is passed substantially horizontally through a leer which Y is in the form of a relatively long tunnel and wherein it may be supported and carried along upon a series of spaced rolls. vDuring the passage of the sheet through the leer, the strains set up in the sheet during the formation thereof are adapted to be relieved and in addition, the said sheet is gradually reduced froma relatively high temperature to atemperature at which it can be readily handled. l/Vhen utilizing such a leer as described above, however, there is a tendency for the sheet to cool more rapidly along the edges'or border portions thereof than at its center due principally to the dissipation of heat through the relatively cool side walls of the leer which is caused by radiation or by the fanning effect of air currents on the outside. This 11n-uniform cooling of the sheet is, of course, an undesirable condi-v tion since it results in an un-uniform annealing thereof which adverselyr affects the sheet and is very apt to cause breakage thereof.

The principal aim and object therefore of this invention is the provision of means disposed within the leer for maintaining a more uniform temperature condition therein transversely thereof with the result that the sheet will be more uniformly annealed throughout its width than `heretofore so` that breakage due to 11n-uniform annealing will be reduced to a minimum. Y

Another object of this invention is the provision of means disposed within the leer opposite the edges of the sheet for reducing to a minimum radiation of heat from the said edges to the cold side walls of the leer whereby to equalize as much as possible the temperature conditions within the leer above the sheet.

Other objects and advantages of the invention will become more apparent during the course of the following description when 1931. v serial No. ascesa taken in connection drawing.

In the drawing wherein like numerals are employed to designate like parts throughout the same,

' Fig. 1 is a vertical longitudinal section through an annealing leer provided by the presentinvention, and y Fig. 2 is a transverse section thereof.

Referring now to the drawing, the annealing leer illustrated therein is designated in its entiretyby the numeral 5, saidV leer being preferably of tunnel-like formation and including a bottom 6, spaced vertical side walls 7 ,and a horizontal top 8.

Arranged within the leer for supporting and conveying the glass sheet 9 therethrough are a plurality of horizontally aligned rolls 10, the shafts or trunnions 11 of which project through plug members 12 mounted in the side walls of the leer. These rolls are preferably positively driven in, unison in any preferred or well known manner to advance the sheet through the leer.

Ordinarily the sheet, when entering the anhealing leer, is quite hot, and in addition to the heat of the sheet, the leer vmay be further heated by a plurality of spaced burners 13 extending transversely thereof so that the sheetis not passed into a chamber whose temperature is much cooler than the chambers in which the sheet is formed. The temperature of the leer is gradually reduced until the sheet passes out of the leer where it can be handled very easily.

In accordance with the present invention, the objects setvforth herein above are accomplishedby the provision of the vertical curtain or partition members 141 and 15 which .arev disposed within the leer opposite to and outwardly of the edges of the glass sheet 9.

The curtain members 14 and 15, which may be-ofasbesto's or some other suitable material, are arranged substantially parallel with the side-'walls 7 of the leer inwardly thereof so that spaces 16 are provided between the said curtain members and the leer walls. The curtain members extend from the roof 8 of the leer downwardly to the rolls l10 and each curwith the accompanying` oF ToLnnoQonIo, Assrenon To LIBBnY-ownns-Fonn Grass co-lvi- .tain is scalloped at its lower edge, or in other `i words, is provided with a plurality of spaced cut-out portions 17 to receive the shafts or trunnions 11 of the rolls 10 therein. Thus, the vertical curtain members serve to partition off the entire space above the rolls and in fact need not terminate at the rolls as shown, but may continue downwardly ltherebeneath any desirable distance. The 4upper edge portion of each curtain member is burned laterally as at 18 and clamped against the roof 8 of the leer by means of a clamping strip 19 suitably fixed in place. The curtain members may extend the entire length of the leer or throughout any desired portion thereof such as, for example, the so-called critical range of annealing.v Furthermore, any suitable means may be provided for securing the curtain members in place.

Due-to the provision of the asbestos-curbains 14: and 15, it will be readily apparent that the radiation of heat from the border portions of the sheet tothe cold side walls of the leer will be reduced to a minimum with the result' that the temperature above the sheet will .be more nearly equaliZed throughout the width ofthe leer and consequently a more uniform annealing and cooling ofthe sheet will be obtained. A portion of the heat from the burners 13 will, of course, pass upwardly into the spaces 16, and this body of heated air betweentlie side walls of the leerv and the curtainswill also assist in preventing loss of heat from the edges of the sheet tothe side Walls of the leer.

It is to be understood that the form of the invention herewith shown. and described is to be taken as the preferred embodiment of the same, and that various changes in the shape, size and arrangement of, parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims, y

I claim: i Y

1. In sheet glass apparatus, thecombination with an annealing leer of: tunnel formation including means for supporting-and conveying the sheet substantially horizontally therethrough, of vertically disposed curtain members arranged within the leer and positioned opposite the sheet outwardly ofthe edgesthereof for minimizing radiation of heat from said sheet tothe `side wallsrof saidleer, said members being spaced inwardly fromthe side walls of the leer and extending from the top of the leer downwardly'to the Vconveying means, the bottom edges of the curtain members being spaced from the bot'- tom of the annealing leer'. Y

2. In sheet glass apparatus, the combination with an annealing leer of tunnelformation including means for` supporting and conveying the sheet substantially. horizontalyly therethrough, of vertically.` disposed curpositioned opposite the sheet outwardly of the edges thereof for minimizing radiation of heat from said sheet to the side walls of said leer, said members being spaced inwardly from the side walls of the leer and extending from the top`v of` tlie.leer downward'ly to the conveying means, the bottom edges of the curtain members being spaced from the bottom of the annealing leer, the said'curtain members being also' formed at their lower edges without-away portions to Yreceive a portion of the sheet supporting and conveying means therein.

3In sheet glass apparatus, the combination with an annealing leer of tunnel forthe leer beneath thev conveying means and ,4

curtains. y. j 1 Y A 1,

4. In sheet glass apparatus, the combination with an annealing leerof tunnelformation including means for supporting and conveyingk the sheet substantially horizontal- .r

ly therethrough,l of vertically disposed curtain. members arranged withinsthe leer f, and positioned opposite the sheet outwardly of the edges thereof for minimizing. radiation ofheat from said sheet yto the side walls of v saidlevensaid members being/spacedzinwardly fromv the side walls vof the leer and extending, from thetop ofthe leer downwardly; to the sheet supporting and Vconveying means,

the bottom edgesof the curtainmembersbeing spaced from the bottom ofthe annealing leer, and heating` means 'arranged within vthe leer. beneath the VConveying..meansand cur.,- tains, the said members being provided with cut-away portions at their lower edges to receive a portionk of the sheet supporting and conveyingmeans therein. y i i Signed at Toledo in the county ofLucas and State of Ohio, this 9th day of May, A1931.

` JOHN L. BRAKE.,

tain members arranged within the leerand 

